Interactions between the Craniomandibular System and Cervical Spine. The influence of an unilateral change of occlusion on the upper cervical range of motion

Interactions between the Craniomandibular System and Cervical Spine. The influence of an unilateral change of occlusion on the upper cervical range of motionThe influence of an unilateral change of occlusion on the upper cervical range of motionvonKlemm, Stephan
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Interactions between the Craniomandibular System and Cervical Spine. The influence of an unilateral change of occlusion on the upper cervical range of motion

This prospective, randomized, double-blind investigation evaluated the influence of a short-time artificial change of occlusion to the upper cervical spine mobility. Twenty 14-19 aged female dancers were investigated in a cross-over-design on head movement rotation in anteflexion with a three-dimensional ultrasonic measurement device, the Zebris 3D Motion Analyzer (CMS 70 P). A change of the occlusion was produced by positioning a 0.75mm foil of tin between premolar and first molar of the right side. Towards the current theory of convergence of cervical and trigeminal nerves the change of occlusion should enlarge tensions in the suboccipital muscles and consequently decrease the mobility of the upper spine. The results of this investigation are: There were no significant differences in measuring movements of the upper cervical spine in dependence of changes of the occlusion. Assessments of the probationers to the changes in tension or motion support these results.

Interactions between the Craniomandibular System and Cervical Spine. The influence of an unilateral change of occlusion on the upper cervical range of motion

Chapter 2.2.2.3, Functional interactions between the masticatory musculature and the anterior and posterior neck musculature:There is no direct muscular connection between the mandible and the CS. However, an indirect connection between the CS and CMS is revealed if the overlapping functions of the musculature of the CMS region with the posterior cervical musculature of the CS exists.This connection is important for the integrated functioning of the head and jaw. Muscular connections are due to a closed chain of muscles in the CMS. Anteriorly, muscles connect the skull to the mandible (the masticatory muscles, see above). Inferiorly, the mandible is anchored to the shoulder girdle via the hyoid (supra and infrahyoid muscles, see above). Posteriorly, the cervical muscles connect the cranium to the shoulder girdle. Therefore, contraction of one muscle will pull on the neighbouring muscle/bone and set up a chain of force disturbing the balance of the whole system. This demonstrates that disorders of the masticatory apparatus, e.g., hyper- or hypotonicity, can disturb the balance of the posterior cervical musculature and vice versa. Since dysfunction of the CMS or cervical spine can cause dysfunctions in related musculature and disturbance of the musculature can cause altered functioning in the joints, these two areas are quite intimately linked by virtue of this muscular chain. Within the framework of their study "Craniomandibular system and spinal column", Stiesch-Scholz & Fink describe the interactions between CMS and CS musculature through the movements for extension and flexion. This includes the fact that when the CS is extended by the infra- and suprahyoid musculature as well as by the increased tension in the soft tissue of the anterior neck, retraction of the mandible occurs and the interocclusal distance is increased in the resting position. In contrast, a flexion of the CS and protrusion of the mandible results in a decrease in the interocclusal distance. Therefore, the integrated functioning of this chain model is also an important demonstration of interactions between CMS and the craniocervical system (CCS) (see Fig. 9, page 29).Functional connections between the CMS, CS and shoulder girdle regions:A description of the numerous neuroanatomical and biomechanical anatomical connections between the CMS and the cervical spine has been given and now the connections within the functioning system will be discussed. Much of the integrated functioning occurs because of the close anatomical relationships and the essential requirement for appropriate head movements whilst talking, eating, swallowing etc. It is doubtful if the human lineage would have got very far in its evolution if the heads had been allowed to bob up and down at the neck due to jaw movements every time the individual talked or chewed.Sherrington stated: "Posture is the basis of all movement and all movement begins and ends in posture". In other words, if posture is faulty, then any subsequent movements will be faulty. It is therefore necessary to first describe the functional interactions between the postural/main musculature of the CMS and CCS according to different postures of the head. Then the effects of the mandibular position on the CCS region will be illustrated. Furthermore, the effects of occlusion on the CMS and CS regions will be highlighted.Head posture: The ideal posture of the head places the centre of gravity slightly anterior to the occipital condyles and, therefore, anterior to the cervical spine. The head tends to nod anteriorly on the spine, as when a person falls asleep in a sitting position. Therefore, the head has to be actively held upright, a function performed by the powerful posterior cervical muscles, which support the weight of the head against gravity. The anterior cervical muscles are much smaller and more weakly developed as gravity aids in their functioning.This may not seem a very efficient form of functioning, but it is the p